Moderate consumption of wine is associated with reduced cardiovascular events, but the mechanism is not fully elucidated. Aim of the study was to seek if consumption of red or white wine, that are known to have different amount of polyphenols, differently influenced platelet aggregation. 20 healthy subjects were randomly allocated to consume for two weeks 300 ml of red or white wine; both wines had the same concentration of alcohol. At baseline and 12 hours after last drink collagen-induced platelet aggregation was performed. At baseline no difference of laboratory values was observed between the two groups. At the end of treatment subjects given red wine had lower response to platelet agonist than those given white wine (<0.005). No ethanol could be found in plasma 12 hours after last drink. This study shows that red and white wine have different effect on platelet activation likely because of the different content of polyphenols present in the two types of wine.